Electronic Components Datasheet Search |
|
PCA1461U Datasheet(PDF) 8 Page - NXP Semiconductors |
|
PCA1461U Datasheet(HTML) 8 Page - NXP Semiconductors |
8 / 24 page 1998 Apr 21 8 Philips Semiconductors Product specification 32 kHz watch circuits with adaptive motor pulse PCA146x series Detection criteria The PCA146x uses current detection in two defined parts of the detection phase to determine if the motor has moved (refer to Figs 6 and 7). The detection criteria are: part 1 • Minimum value of P = 1; where P = number of measured positive current polarities after tDI. part 2 • Minimum value of N = 2; where N = number of measured positive current polarities since the first negative current polarity after part 1 was detected (see Fig.6). If the opposite polarity is measured in one part, the internal counter is reset, so the results of all measurements in this part are ignored. The waveform of the induced current must enable all these measurements within the time tD after the end of a positive motor pulse in order to be accepted as a waveform of an executed motor pulse. If the detection criterion is satisfied earlier, a measurement cycle will not be started and the switches P1 and P2 stay closed, the motor is switched to VDD. Every measurement cycle (tMC) has 4 phases. These are detailed in Table 1. Note that detection and pulse width control will be switched OFF when the battery voltage is below the end-of-life voltage (VEOL), or if stage 5 is not sufficient to turn the motor. Table 1 Measurement cycle SYMBOL PHASE DESCRIPTION tM1 1 During tM1 the switches P1 and P2 are closed in order to switch the motor to VDD, so the induced current flows unaffected through the motor inductance. tM2 2 Measures the induced current; during a maximum time tM2 all switches are open until a change is sensed by one of the level detectors (L1, L2). The motor is short-circuited to VDD. Depending on the direction of the interrupted current: • The current flows through diodes D3 and D2, causing the voltage at M1 to decrease in relation to M2; • The current flows through diodes D4 and D1, causing the voltage at M2 to decrease in relation to M1. A successfully detected current polarity is normally characterized by a short pulse of 0.5 to 10 µs with a voltage up to ±2.1 V, failed polarity detection by the maximum pulse width of 61 µs and a voltage of ±0.5 V (see Fig.7). tM3 3 The switches P1 and P2 remain closed for the time tM3. tM4 4 If the circuit detects fewer pulses than P and N respectively, a pulse of the time tM4 occurs to reduce the induced current. Therefore P2 and P1 are opened and N1 and N2 are closed. Otherwise P1 and P2 remain closed. |
Similar Part No. - PCA1461U |
|
Similar Description - PCA1461U |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |